The Earth has a new follower. Astronomers recently discovered a tiny quasi-moon that they believe has been orbiting the sun alongside the Earth for decades. The new quasi-moon, which is being called ...

Over 4.6 billion years ago, Earth took shape from a spinning cloud of dust and gas surrounding the young sun. Tiny particles within this cloud collided and clumped together, driven by gravity and ...

Approximately 4.5 billion years ago, a planet called Theia slammed into the Earth. The impact melted parts of Earth’s mantle and sent a massive cloud of debris into space. Over time, this debris came ...

Humanity’s need to track the Moon’s changing phases and motions is ancient. Mammoth hunters used the Moon as a timekeeper, carving crescent-shaped notches into bone and tusk. Sumerian astronomers ...

The Earth stands alone in the solar system as a habitable world, as far as we know. But that doesn’t mean we don’t get visitors, most often in the form of (usually harmless) asteroids. Some even ...